Hi guys,

My 05 RX-8 GT 6-speed is going to have new EBC 3GD rotors on front and rear.

I checked with EBC's website and their fitting micro site, and it showed me following options:

-For standard suspension, front rotor shall be GD7221 (11.9 inch)
-For sports suspension, front rotor shall be GD7171 (12.7 inch).
-Rear rotor are the same, GD7172 (11.9 inch)

The trouble is, I don't know if my car is running with standard suspension or the sport suspension. I do have 18' factory wheel though. (I searched the forum and one guy had trouble in putting the 12.7 inch EBC front rotor on his 16 inch wheel)

I called my dealer/maintaince guy in Mazda, and he told me my 05 is a standard suspension. (I have no idea how he find out this but he does know my name and look up into my record)

I also call 3 resellers including perfectbrake, and none of them are sure about my factory suspension....

However, my front disc appears to be bigger than the rear...(finger measured)

So I wonder for you guys who already have EBC 3GD on front with 18 inch wheel:

1) how do I know if I have sport suspension or standard suspension?
(is sport suspension only available to the Shinka Special Edition in 05 or R3 version are available later 08 models?)

2) Should I order the 11.9 inch or the 12.7 inch for the front, considering I am having a bigger rotor in the front when it comes out of the factory?

Thanks Any help is appreciated!

 

Bump for more attention....

 

Haha, I've been looking at the same thing lately. Did you ever figure out if you have sport suspension or standard? Also, how'd the rotors work out if you got them?

 

All the RX8's have the sport suspension, except the base automatic transmission versions with the 16" wheels. That is why the brake rotors are smaller for that version. The 16" wheels won't fit over the larger rotors.

 

easiest thing is to take out your rotor and measure it.

 

The easy way: Go to the dealership, let the parts department check for you with your VIN--it shows everything comes with your car.

The hard way: remove wheel and measure the rotor.

 

If front-non-sport are 11.9 inches and rear-sport/non-sport are also 11.9 inches - do you think either will fit? Asking because they have different part numbers. Is there another factor involved - or just diameter? Thanks!

 

Thickness is a factor, also hat depth and the diameter of the inside of the friction surface. you can measure those on your car right now and see if they're the same, but I'd bet there are differences.

 

I bought EBC Ultimax rotors all around this last winter. The thicknesses were different. On every front-wheel-drive I've owned, the rear rotors are solid while fronts had venting in between. I believe both front and rear on the RX8 had venting, though.